The Apparatus in Serpents for their Motion is admirable. How curious the
Structure of their Muscles, and their Junction to every Point, whereby
they are prepared for their different Motions, and enabled to move
according to their different Nature and Situation!
In those that go upon their Bellies, the Movement is very singular,
which is in a Form curvilineal, different winding of their Bodies. The
Serpentine Line, among Mathematicians, is borrowed from the Foldings of
a Serpent in its Motion.
The Learned observe, there is a great deal of geometrical Niceness in
the sinuous Motion of Snakes, Vipers, and other Serpents; to assist them
in the right Management of it, the annular Scales under their Bodies are
very remarkable, lying cross the Belly, contrary to what those in the
Back, and the rest of the System do; which Contrivance facilitates their
Motion. This tortuous creeping Motion of the Reptile Species is very
curious: The whole Body of a Worm is, as it were, but a Chain of annular
or spiral Muscles, whose round Fibres, by contracting, make each Ring
more strong. The Back-Bones of Serpents are a wonderful Composition: How
thick are they with Joints? How numerous and strong are their
co-operating Muscles? By this curious Articulation of the Joints, they
can turn and wind their Bodies any way without any difficulty.
The Outside of their Skin is a most elegant Composition: to a common
Eye, their Tegument has a rugged uneven Aspect; but, to a proper Judge,
the Scales of Vipers are found to be a most exquisite Piece of
Mechanism; the Symmetry of the whole is geometrically exact, and vastly
beautiful; not imitable by human Skill: Some of them are guarded by a
coverture not penetrable by a human Arm, which is their Security in a
perilous Situation; yea, a greater Security than many innocent
Inhabitants of the Field are privileged with. Among Serpents, some are
clothed as with a Coat of Mail, _i. e._ an Armature of strong Scales;
and such of them as want that crustaceous Covering, have either a Sting
in the Tail, or a Tooth in their Mouth, that bids the Assailant keep
off, and observe his Distance.
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